At least 20 people were killed and 30 others injured in a blast near a local minister's residence at market area in central Pakistan on Tuesday, local TV channels reported.

The car bomb exploded near the house of provincial minister Dost Muhammad Khosa at the city of Dera Ghazi Khan in Punjab province, Commissioner Hasan Iqbal said.

Iqbal said that up to 40 persons are trapped under the rubbles of the collapsed buildings. Hospital and rescue team sources said that 20 people were killed in the blast.

According to initial reports, a suicide bomber rammed his car at the residence of Muhammad Khosa, damaging the entrance gate and buildings adjacent to his house.

Minister Khosa said that eight members of his family including two cousins were among the injured. He said he was not at home at the time of the blast.

The blast destroyed over 10 shops and caused damage to several houses, witnesses said. According to police sources, five kgs of explosives were used in the blast.

Sources said that the militants may have targeted the house of the minister as his father, Zulfikar Khosa, senior advisor to the Punjab's Chief Minister, organized a conference of religious scholars who issued a decree against suicide attacks.

Commissioner Iqbal said that it was a car bomb and the target was the house of the minister and the market. Several women and children were among the injured who were busy in shopping in the busy market area.

Emergency was declared in local hospitals, the Commissioner said.

Witnesses said that the blast was so powerful that it was heard far and wide and smashed the windowpanes of the nearby buildings. High police officials have reached the scene as rescue operations are underway.

No group claimed responsibility for the blast. But the government blames suspected Taliban for such attacks.?